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/* * To change this license header, choose License Headers in Project Properties.

* To change this template file, choose Tools | Templates * and open the template in the editor.

*/ /** * * @author zyao01 */ /****************************************************************************** * Compilation: javac In.java * Execution: java In (basic test --- see source for required files) * Dependencies: none * * Reads in data of various types from standard input, files, and URLs.

* ******************************************************************************/ package as4autocomplete; import java.io.BufferedInputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.net.Socket; // import java.net.HttpURLConnection; import java.net.URLConnection; import java.util.ArrayList; import java.util.InputMismatchException; import java.util.Locale; import java.util.NoSuchElementException; import java.util.Scanner; import java.util.regex.Pattern; /** * Input. This class provides methods for reading strings * and numbers from standard input, file input, URLs, and sockets.

*

* The Locale used is: language = English, country = US. This is consistent * with the formatting conventions with Java floating-point literals, * command-line arguments (via {@link Double#parseDouble(String)}) * and standard output.

*

* For additional documentation, see * Section 3.1 of * Introduction to Programming in Java: An Interdisciplinary Approach * by Robert Sedgewick and Kevin Wayne.

*

* Like {@link Scanner}, reading a token also consumes preceding Java * whitespace, reading a full line consumes * the following end-of-line delimeter, while reading a character consumes * nothing extra.

*

* Whitespace is defined in {@link Character#isWhitespace(char)}. Newlines * consist of \n, \r, \r\n, and Unicode hex code points 0x2028, 0x2029, 0x0085; * see * Scanner.java (NB: Java 6u23 and earlier uses only \r, \r, \r\n).

* * @author David Pritchard * @author Robert Sedgewick * @author Kevin Wayne */ public final class In { ///// begin: section (1 of 2) of code duplicated from In to StdIn.

// assume Unicode UTF-8 encoding private static final String CHARSET_NAME = "UTF-8"; // assume language = English, country = US for consistency with System.out.

private static final Locale LOCALE = Locale.US; // the default token separator; we maintain the invariant that this value // is held by the scanner's delimiter between calls private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\p{javaWhitespace}+"); // makes whitespace characters significant private static final Pattern EMPTY_PATTERN = Pattern.compile(""); // used to read the entire input. source:

// http://weblogs.java.net/blog/pat/archive/2004/10/stupid_scanner_1.html private static final Pattern EVERYTHING_PATTERN = Pattern.compile("\\A"); //// end: section (1 of 2) of code duplicated from In to StdIn.

private Scanner scanner; /** * Initializes an input stream from standard input.

*/ public In() { scanner = new Scanner(new BufferedInputStream(System.in), CHARSET_NAME); scanner.useLocale(LOCALE); } /** * Initializes an input stream from a socket.

* * @param socket the socket * @throws IllegalArgumentException if cannot open {@code socket} * @throws NullPointerException if {@code socket} is {@code null} */ public In(Socket socket) { if (socket == null) throw new NullPointerException("argument is null"); try { InputStream is = socket.getInputStream(); scanner = new Scanner(new BufferedInputStream(is), CHARSET_NAME); scanner.useLocale(LOCALE); } catch (IOException ioe) { throw new IllegalArgumentException("Could not open " + socket); } } /** * Initializes an input stream from a URL.

* * @param url the URL * @throws IllegalArgumentException if cannot open {@code url} * @throws NullPointerException if {@code url} is {@code null} */ public In(URL url) { if (url == null) throw new NullPointerException("argument is null"); try { URLConnection site = url.openConnection(); InputStream is = site.getInputStream(); scanner = new Scanner(new BufferedInputStream(is), CHARSET_NAME); scanner.useLocale(LOCALE); } catch (IOException ioe) { throw new IllegalArgumentException("Could not open " + url); } } /** * Initializes an input stream from a file.

* * @param file the file * @throws IllegalArgumentException if cannot open {@code file} * @throws NullPointerException if {@code file} is {@code null} */ public In(File file) { if (file == null) throw new NullPointerException("argument is null"); try { scanner = new Scanner(file, CHARSET_NAME); scanner.useLocale(LOCALE); } catch (IOException ioe) { throw new IllegalArgumentException("Could not open " + file); } } /** * Initializes an input stream from a filename or web page name.

* * @param name the filename or web page name * @throws IllegalArgumentException if cannot open {@code name} as * a file or URL * @throws NullPointerException if {@code name} is {@code null} */ public In(String name) { if (name == null) throw new NullPointerException("argument is null"); try { // first try to read file from local file system File file = new File(name); if (file.exists()) { scanner = new Scanner(file, CHARSET_NAME); scanner.useLocale(LOCALE); return; } // next try for files included in jar URL url = getClass().getResource(name); // or URL from web if (url == null) { url = new URL(name); } URLConnection site = url.openConnection(); // in order to set User-Agent, replace above line with these two // HttpURLConnection site = (HttpURLConnection) url.openConnection(); // site.addRequestProperty("User-Agent", "Mozilla/4.76"); InputStream is = site.getInputStream(); scanner = new Scanner(new BufferedInputStream(is), CHARSET_NAME); scanner.useLocale(LOCALE); } catch (IOException ioe) { throw new IllegalArgumentException("Could not open " + name); } } /** * Initializes an input stream from a given {@link Scanner} source; use with * new Scanner(String) to read from a string.

*

* Note that this does not create a defensive copy, so the * scanner will be mutated as you read on.

* * @param scanner the scanner * @throws NullPointerException if {@code scanner} is {@code null} */ public In(Scanner scanner) { if (scanner == null) throw new NullPointerException("argument is null"); this.scanner = scanner; } /** * Returns true if this input stream exists.

* * @return true if this input stream exists; false otherwise */ public boolean exists() { return scanner != null; } //// begin: section (2 of 2) of code duplicated from In to StdIn, //// with all methods changed from "public" to "public static".

/** * Returns true if input stream is empty (except possibly whitespace).

* Use this to know whether the next call to {@link #readString()}, * {@link #readDouble()}, etc will succeed.

* * @return true if this input stream is empty (except possibly whitespace); * false otherwise */ public boolean isEmpty() { return !scanner.hasNext(); } /** * Returns true if this input stream has a next line.

* Use this method to know whether the * next call to {@link #readLine()} will succeed.

* This method is functionally equivalent to {@link #hasNextChar()}.

* * @return true if this input stream is empty; * false otherwise */ public boolean hasNextLine() { return scanner.hasNextLine(); } /** * Returns true if this input stream has more inputy (including whitespace).

* Use this method to know whether the next call to {@link #readChar()} will succeed.

* This method is functionally equivalent to {@link #hasNextLine()}.

* * @return true if this input stream has more input (including whitespace); * false otherwise */ public boolean hasNextChar() { scanner.useDelimiter(EMPTY_PATTERN); boolean result = scanner.hasNext(); scanner.useDelimiter(WHITESPACE_PATTERN); return result; } /** * Reads and returns the next line in this input stream.

* * @return the next line in this input stream; null if no such line */ public String readLine() { String line; try { line = scanner.nextLine(); } catch (NoSuchElementException e) { line = null; } return line; } /** * Reads and returns the next character in this input stream.

* * @return the next character in this input stream */ public char readChar() { scanner.useDelimiter(EMPTY_PATTERN); String ch = scanner.next(); assert ch.length() == 1 : "Internal (Std)In.readChar() error!" + " Please contact the authors."; scanner.useDelimiter(WHITESPACE_PATTERN); return ch.charAt(0); } /** * Reads and returns the remainder of this input stream, as a string.

* * @return the remainder of this input stream, as a string */ public String readAll() { if (!scanner.hasNextLine()) return ""; String result = scanner.useDelimiter(EVERYTHING_PATTERN).next(); // not that important to reset delimeter, since now scanner is empty scanner.useDelimiter(WHITESPACE_PATTERN); // but let's do it anyway return result; } /** * Reads the next token from this input stream and returns it as a String.

* * @return the next String in this input stream */ public String readString() { return scanner.next(); } /** * Reads the next token from this input stream, parses it as a int, * and returns the int.

* * @return the next int in this input stream */ public int readInt() { return scanner.nextInt(); } /** * Reads the next token from this input stream, parses it as a double, * and returns the double.

* * @return the next double in this input stream */ public double readDouble() { return scanner.nextDouble(); } /** * Reads the next token from this input stream, parses it as a float, * and returns the float.

* * @return the next float in this input stream */ public float readFloat() { return scanner.nextFloat(); } /** * Reads the next token from this input stream, parses it as a long, * and returns the long.

* * @return the next long in this input stream */ public long readLong() { return scanner.nextLong(); } /** * Reads the next token from this input stream, parses it as a short, * and returns the short.

* * @return the next short in this input stream */ public short readShort() { return scanner.nextShort(); } /** * Reads the next token from this input stream, parses it as a byte, * and returns the byte.

*

* To read binary data, use {@link BinaryIn}.

* * @return the next byte in this input stream */ public byte readByte() { return scanner.nextByte(); } /** * Reads the next token from this input stream, parses it as a boolean * (interpreting either "true" or "1" as true, * and either "false" or "0" as false).

* * @return the next boolean in this input stream */ public boolean readBoolean() { String s = readString(); if (s.equalsIgnoreCase("true")) return true; if (s.equalsIgnoreCase("false")) return false; if (s.equals("1")) return true; if (s.equals("0")) return false; throw new InputMismatchException(); } /** * Reads all remaining tokens from this input stream and returns them as * an array of strings.

* * @return all remaining tokens in this input stream, as an array of strings */ public String[] readAllStrings() { // we could use readAll.trim().split(), but that's not consistent // since trim() uses characters 0x00..0x20 as whitespace String[] tokens = WHITESPACE_PATTERN.split(readAll()); if (tokens.length == 0 || tokens[0].length() > 0) return tokens; String[] decapitokens = new String[tokens.length-1]; for (int i = 0; i < tokens.length-1; i++) decapitokens[i] = tokens[i+1]; return decapitokens; } /** * Reads all remaining lines from this input stream and returns them as * an array of strings.

* * @return all remaining lines in this input stream, as an array of strings */ public String[] readAllLines() { ArrayList lines = new ArrayList(); while (hasNextLine()) { lines.add(readLine()); } return lines.toArray(new String[0]); } /** * Reads all remaining tokens from this input stream, parses them as integers, * and returns them as an array of integers.

* * @return all remaining lines in this input stream, as an array of integers */ public int[] readAllInts() { String[] fields = readAllStrings(); int[] vals = new int[fields.length]; for (int i = 0; i < fields.length; i++) vals[i] = Integer.parseInt(fields[i]); return vals; } /** * Reads all remaining tokens from this input stream, parses them as doubles, * and returns them as an array of doubles.

* * @return all remaining lines in this input stream, as an array of doubles */ public double[] readAllDoubles() { String[] fields = readAllStrings(); double[] vals = new double[fields.length]; for (int i = 0; i < fields.length; i++) vals[i] = Double.parseDouble(fields[i]); return vals; } ///// end: section (2 of 2) of code duplicated from In to StdIn */ /** * Closes this input stream.

*/ public void close() { scanner.close(); } /** * Reads all integers from a file and returns them as * an array of integers.

* * @param filename the name of the file * @return the integers in the file * @deprecated Replaced by new In(filename).{@link #readAllInts()}.

*/ public static int[] readInts(String filename) { return new In(filename).readAllInts(); } /** * Reads all doubles from a file and returns them as * an array of doubles.

* * @param filename the name of the file * @return the doubles in the file * @deprecated Replaced by new In(filename).{@link #readAllDoubles()}.

*/ public static double[] readDoubles(String filename) { return new In(filename).readAllDoubles(); } /** * Reads all strings from a file and returns them as * an array of strings.

* * @param filename the name of the file * @return the strings in the file * @deprecated Replaced by new In(filename).{@link #readAllStrings()}.

*/ public static String[] readStrings(String filename) { return new In(filename).readAllStrings(); } /** * Reads all integers from standard input and returns them * an array of integers.

* * @return the integers on standard input * @deprecated Replaced by {@link StdIn#readAllInts()}.

*/ public static int[] readInts() { return new In().readAllInts(); } /** * Reads all doubles from standard input and returns them as * an array of doubles.

* * @return the doubles on standard input * @deprecated Replaced by {@link StdIn#readAllDoubles()}.

*/ public static double[] readDoubles() { return new In().readAllDoubles(); } /** * Reads all strings from standard input and returns them as * an array of strings.

* * @return the strings on standard input * @deprecated Replaced by {@link StdIn#readAllStrings()}.

*/ public static String[] readStrings() { return new In().readAllStrings(); } /** * Unit tests the In data type.

*/ public static void main(String[] args) { In in; String urlName = "http://introcs.cs.princeton.edu/stdlib/InTest.txt"; // read from a URL System.out.println("readAll() from URL " + urlName); System.out.println("---------------------------------------------------------------------------"); try { in = new In(urlName); System.out.println(in.readAll()); } catch (Exception e) { System.out.println(e); } System.out.println(); // read one line at a time from URL System.out.println("readLine() from URL " + urlName); System.out.println("---------------------------------------------------------------------------"); try { in = new In(urlName); while (!in.isEmpty()) { String s = in.readLine(); System.out.println(s); } } catch (Exception e) { System.out.println(e); } System.out.println(); // read one string at a time from URL System.out.println("readString() from URL " + urlName); System.out.println("---------------------------------------------------------------------------"); try { in = new In(urlName); while (!in.isEmpty()) { String s = in.readString(); System.out.println(s); } } catch (Exception e) { System.out.println(e); } System.out.println(); // read one line at a time from file in current directory System.out.println("readLine() from current directory"); System.out.println("---------------------------------------------------------------------------"); try { in = new In("./InTest.txt"); while (!in.isEmpty()) { String s = in.readLine(); System.out.println(s); } } catch (Exception e) { System.out.println(e); } System.out.println(); // read one line at a time from file using relative path System.out.println("readLine() from relative path"); System.out.println("---------------------------------------------------------------------------"); try { in = new In("../stdlib/InTest.txt"); while (!in.isEmpty()) { String s = in.readLine(); System.out.println(s); } } catch (Exception e) { System.out.println(e); } System.out.println(); // read one char at a time System.out.println("readChar() from file"); System.out.println("---------------------------------------------------------------------------"); try { in = new In("InTest.txt"); while (!in.isEmpty()) { char c = in.readChar(); System.out.print(c); } } catch (Exception e) { System.out.println(e); } System.out.println(); System.out.println(); // read one line at a time from absolute OS X / Linux path System.out.println("readLine() from absolute OS X / Linux path"); System.out.println("---------------------------------------------------------------------------"); in = new In("/n/fs/introcs/www/java/stdlib/InTest.txt"); try { while (!in.isEmpty()) { String s = in.readLine(); System.out.println(s); } } catch (Exception e) { System.out.println(e); } System.out.println(); // read one line at a time from absolute Windows path System.out.println("readLine() from absolute Windows path"); System.out.println("---------------------------------------------------------------------------"); try { in = new In("G:\\www\\introcs\\stdlib\\InTest.txt"); while (!in.isEmpty()) { String s = in.readLine(); System.out.println(s); } System.out.println(); } catch (Exception e) { System.out.println(e); } System.out.println(); } } /****************************************************************************** * Copyright 2002-2015, Robert Sedgewick and Kevin Wayne.

* * This file is part of algs4.jar, which accompanies the textbook * * Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne, * Addison-Wesley Professional, 2011, ISBN 0-321-57351-X.

* http://algs4.cs.princeton.edu * * * algs4.jar is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version.

* * algs4.jar is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details.

* * You should have received a copy of the GNU General Public License * along with algs4.jar. If not, see http://www.gnu.org/licenses.

******************************************************************************/

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